Demand Ventilation Hood Controls - Northern California

Demand Ventilation Control Systems
Commercial Kitchens
February 24, 2012
Presented By:
Mike Dean
 What is DVC for CKV?
 Demand Ventilation Controls for Commercial Kitchen Ventilation
 True “demand ventilation” control system designed specifically
for commercial kitchens.
 A controls package that can be “retro-fitted” to a commercial
kitchen exhaust hood, or designed into a “new construction”
 Controls the grease exhaust and make-up air unit fan motors for
each exhaust hood system.
 VFD’s modulate exhaust fans based on a controlled input,
exhaust air temperature, and make-up air fans are then
controlled proportional to exhaust.
 History
Traditional kitchen ventilation systems have been controlled
by basic electro-mechanical interlocks for years.
NFPA 96 required grease exhaust duct velocities of 1,5002,500 fpm up until 2002. This forced mechanical engineers
into constant volume designs for many years
January 2002 NFPA issued Errata 96-01-01 changing
Section to read “ The air velocity through any duct
shall be not less than 152.4 m/min (500 ft/min)”
 History
This single revision allowed the traditional constant volume
kitchen ventilation system to enter into the world of variable
2004 first Melink Intelli-Hood system installed in California
Energy conservation became trendy…..and…..more openly
 History
UC/CSU/CCC Campuses
ASHRAE 90.1/189.1
CEC PIER Technology
 Codes/Standards
ASHRAE 90.1-2010 Section Kitchen Exhaust Systems
1. If a kitchen/dining facility has a total kitchen exhaust airflow rate
greater than 5,000 cfm then it shall have one of the following:
a) At least 50% of all replacement air is transfer air that would
otherwise be exhausted.
b) Demand ventilation system(s) on at least 75% of the
exhaust air. Such systems shall be capable of at least 50%
reduction in exhaust and replacement air system airflow
rates, including controls necessary to modulate airflow in
response to appliance operation and to maintain full capture
and containment of smoke, effluent and combustion
products during cooking and idle.
c) Listed energy recovery devices with a sensible heat
recovery effectiveness of not less than 40% on at least 50%
of the total exhaust airflow
 Codes/Standards
ASHRAE 189.1-2009 Standard for the Design of High-Performance Green Buildings
Except Low-Rise Residential Buildings
Variable-Speed Fan Control for Commercial Kitchen Hoods.
In addition to the requirements in Section of ANSI/ASHRAE/IESNA Standard
90.1, commercial kitchen Type I and Type II hood systems shall have variable-speed
control for exhaust and make-up air fans to reduce hood airflow rates at least 50%
during those times when cooking is not occurring and the coking appliances are up to
temperature in a standby, ready-to-cook mode.
All exceptions in Section of ANSI/ASHRAE/IESNA Standard 90.1 shall apply.
 Why is this important? Changes to Standards, and Codes,
show a growing trend towards the adoption of the
technology across the board
 Now What?
CaptiveAire EMSplus
Melink Intelli-Hood
(OEM by: Greenheck, Accurex
Kees, Gaylord)
Spring Air TruFlow
PG&E Food Service Technology Center
Temperature Sensor
Allen Bradley
or ABB ACH550
Series VFD’s
Air Purge Unit
I/O Processor
Infrared Optic Sensor
Keypad Mounted
At Pull-Station
Optic Sensors Mounted Inside Hood Canopy
Variable Frequency Drives
The heart of variable volume controls
Melink Intelli-Hood Video
 So, now we have a new demand ventilation control system. How
do we incorporate existing HVAC systems and proper air balance
 Commercial Kitchens and Restaurants are typically very “leaky”
facilities and present different air balance challenges:
Diner’s entering and exiting the main doors
Competing ventilation systems. i.e. Dining area air conditioning Versus kitchen
ventilation (and now modulated hood exhaust)
Receiving doors blocked open
“House” ventilation transferred to kitchen as additional make-up air
 DVC systems operate dynamically between their preset minimum
fan speeds and maximum ventilation system design airflows.
Balance at full speed
Verify airflows at minimum fan speeds
Let the systems modulate and save energy
 Our Top 5
1. Avoid degrading exhaust hood capture and containment at all
costs! Verify capture and containment at minimum design
2. Control exhaust and make-up air whenever possible
3. Pre-balance all retro-fit projects. Will typically uncover existing
underlying problems
4. Integrate with building EMS systems so that the individual
systems work together
5. Commission, commission, commission!
 Ultimately, a properly balanced ventilation system with proper
capture and containment at the exhaust hood creates a happy
 Proper Capture and Containment – Our Ultimate Goal
Schlieren Video
OK, Now The Real World
OK, Now The Real World
Frayed Belt
Fan Not
To Base
Pool of Oil
Cat Litter
Exhaust Hood Capture Problem – Palo Alto Restaurant
OK, Now The Real World
Noise and Velocity Issue at Zagat Rated Restaurant in San Francisco
Perfect World Application for DVC – matched systems
 Demand Ventilation Controls Save Energy!
 Several Utilities offer direct incentives for these systems in both
“Deemed” and “Calculated” energy efficiency measures:
Southern California Edison
SoCal Gas
Silicon Valley Power
City of Palo Alto Utilities
Constant Volume Kitchen Ventilation
Systems Waste Energy!
[email protected]
Mike: 916.596.0085 x801

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